IF COST IS NOT A PROBLEME
then should we make all the buildings by using titanium??????

Even if you factor out cost, there isn't a universally superior material for all applications, imo, even if we strict ourselves to 'basic' metallic materials. Coming up with construction applications where any can be seen better with some criterion, considering the vast diversities within even these 3, isn't all that difficult. If you want to limit your question further, then something, e.g. titanium can surface.